摘要:
A magnetic tape transport controller for a magnetic recording and reproducing apparatus in which a pilot signal for tracking control having four different frequencies is recorded on a magnetic tape by a rotary magnetic head and the magnetic tape is transported in a playback mode at a different tape speed than that in a recording mode. The tape transport controller has means for detecting an amplitude change of a specific one of signals derived by frequency-converting a reproduced pilot signal and controlling the tape speed such that the frequency of the amplitude change is maintained at a predetermined frequency. It also has a phase control loop to control the tape speed such that a phase of the specific signal coincides with a phase of a reference signal. In the playback mode in which the tape is transported at the different speed than that in the recording mode, frequencies of a local pilot signal used to frequency-convert the reproduced pilot signal are switched in the opposite order to that of the switching of the frequencies in the recording mode. A detection circuit which detects a difference between two frequency converted signals of different frequencies and amplifies the difference inverts a polarity of an output signal for each track switching in a standard speed playback mode and does not invert the polarity in a variable speed playback mode.
摘要:
A tracking control device for use in a rotary magnetic head type magnetic recording/reproducing apparatus, having a device for generating synchronizing signals in synchronism with the rotation of rotary magnetic heads, at a recording mode, records on a magnetic tape original information signals time-base converted so that the synchronizing information included in the information signals is in a predetermined synchronizing relation with said synchronizing signals, together with said synchronizing information; and at a reproduction mode of the recorded information, time-base converts the information signals and synchronizing information to restore the original information and controls the relative speed between the magnetic tape and rotary magnetic heads so that the time of the phase difference between the synchronizing signals and the reproduced synchronizing information is a predetermined value.
摘要:
A device for controlling consecutive recording of video information containing signals, on a magnetic recording medium in a magnetic recording and reproducing apparatus, fed from a video camera with variable time spacing. The device comprises a control switch rendered non-conductive or conductive when a pause switch in the magnetic recording and reproducing apparatus is actuated or released, and a member for initializing a sync signal generator in the video camera with a signal produced in synchronism with the rotation of a head carrying disc driving motor of the magnetic recording and reproducing apparatus, whereby energy consumption is lowered and synchronization between successive video information signals is attained rapidly during the consecutive recording of video information signals from the video camera.
摘要:
A detector circuit for detecting a phase or frequency error of an input signal. One mode of at least two detection modes is selected according to a phase or a frequency of the input signal with each mode having a reference value of a phase or a frequency of the input signal and reference values of the detection modes being different from each other. A pulse signal having a phase corresponding to a difference between an actual phase or frequency of the input signal and the reference value of the phase or the frequency is generated, and a predetermined carrier signal is pulse width modulated with a predetermined modulation factor in response to the pulse signal, the modulation factor being different for each detection mode.
摘要:
In a rotary magnetic head helical scan type video tape recorder using a segment recording system, a video signal of one vertical scanning period is divided into n video signal blocks, where n is an integer equal to or larger than 2, and a redundant period having a selected length is inserted into the video signal blocks in a recording mode. Each of the video signal blocks has a number of horizontal scanning lines equal or smaller than N/n, where N is the number of the horizontal scanning lines in a field of the video signal. In a reproducing mode, a time axis error of reproduced series of the video signal blocks is corrected at least during the redunant periods. Then, the corrected blocks are converted into the original video signal.
摘要:
Herein disclosed is a gas switch comprising: a body casing having an arc-extinguishing gas such as the SF6 gas and the like confined therein; bushings having their inner end portions inserted into said body casing; a rod-shaped stationary electrode and a hollow stationary electrode attached to the inner end portions of the bushings movable electrodes contacting with the rod-shaped stationary electrode at all times and made movable into and out of contact with said hollow stationary electrode; insulated bearing sleeves bearing the movable electrodes, respectively; a plurality of rocking arms for rocking in association with the turn of a drive shaft so that the movable electrodes are linearly moved through the insulated bearing sleeves by the rocking motions of the rocking arms to open and close the gas switch; and a connecting mechanism for connecting the rocking arms to the insulated bearing sleeves, respectively. The connecting mechanism includes: engaging grooves formed in the outer sides of the insulated bearing sleeves and opened at their sides facing the drive shaft; and engaging projections so formed in portions of the rocking arms as to directly engage with the engaging grooves and allowing in their engaging states the rocking arms to rock in the engaging grooves.
摘要:
In a helical scanning type video tape recorder provided with two rotary video heads for recording and reproducing a video signal supplied to the heads in the oblique direction of a magnetic tape by alternately switching the two rotary video heads, there is generated a switching signal for the heads which is stable in standard and high speed reproducing modes and thereby stable reproduction always can be obtained. For this purpose, there are provided a circuit for detecting the rotary phase of any one of the two rotary heads, a clock signal generator circuit for generating a clock signal, a counter apparatus for counting the clock signal on the basis of the output of the rotary phase detecting circuit, and a circuit for generating a switching signal for alternately switching the two heads on the basis of the counted value of the counter apparatus.
摘要:
A method for transmitting a color video signal on a narrow-band transmission line such as a telephone line or an audio tape recorder is disclosed. The carrier frequency is so reduced that no clock signal of high frequency is used. The carrier chrominance signal and the brightness or luminance signal are transmitted separately in time-division multiplication thereby to eliminate color distortion. The write clock signal frequency for the carrier chrominance signal is rendered inversely proportional to the product of a given number determined by the number of samples required for faithful transmission of the carrier chrominance signal and a multiple enabling the carrier frequency to be minimized. The read clock signal frequency for the carrier chrominance signal is reduced to one over an integer of the luminance signal, so that the carrier chrominance signal is read at intervals of the integer in order of storage in a memory. At the time of writing the color chrominance signal in the memory, the write clock frequency therefor is rendered equal to the write clock frequency for the luminance signal. Thus the capacity of the memory for the carrier chrominance signal is one over an integer of that for the luminance signal.
摘要:
A method of reproducing video signals from a magnetic recording medium like a magnetic tape for a VTR to obtain high-quality video pictures even when dropouts occur in the medium, which includes the steps of separating synchronizing information from the video signals reproduced from the magnetic recording medium, detecting a dropout duration from the reproduced video signals, generating complete synchronizing information during a whole period of writing the signals in image information memories by compensating lost synchronizing information during the dropout, generating write address signals on the basis of the generated synchronizing information, writing reproduced video signals the memories on the basis of the generated write address signals while no dropout occurs, and leaving unchanged previously written video signals while a dropout occurs. According to an apparatus implementing the above method, reproduced pictures of high quality are obtained without jitters and skews due to dropouts.
摘要:
A signal processing method or apparatus in which an input signal is converted to a signal of a predetermined frequency characteristic and the resulting signal is reconverted to a signal of the original frequency characteristic, comprising: a first signal processing section for processing the input signal and having the first transfer function exp(-msT)/(1+K.multidot.cos(.omega.T) or a function approximating to the former function; a second signal processing section cascaded with the first signal processing section for processing the input signal and having a second transfer function of (1+K.multidot.cos(.omega.T).multidot.exp(-sT)), the first signal processing section having a linear phase characteristic and including an impedance circuit or an admittance circuit, each circuit including a ladder network of a plurality of inductance elements and capacitance elements.